1. Technical Field
The present invention relates to an apparatus and a method for controlling a speed of a motor, and more particularly, to an apparatus and a method for controlling a speed of a motor capable of reducing a time delay due to a speed detection calculation and an error in a detection speed due to the time delay, in a speed detection method of a revolution per minute (RPM) type according to the related art.
2. Description of the Related Art
Various configurations of a motor control circuit have been known. One of the configurations is the very H-bridge or full bridge configuration. In the H-bridge or full-bridge configuration, four transistors form an H pattern, together with a motor coil connected so as to form a H-shaped bridge. Transistor switches are formed in pair and are controlled. When a first switch pair is conducted, a first voltage signal is applied to the motor coil to generate current flowing in a first direction to the coil and when a second switch pair is conducted, a second voltage signal is applied to the motor coil to generate current flowing in an opposite direction to the coil. A speed of a motor is controlled according to a turn-on/off ratio of the transistor pairs.
Meanwhile, FIG. 1 is a diagram schematically illustrating a configuration of an example of an apparatus for controlling a speed of a motor according to the related art.
Referring to FIG. 1, an apparatus for controlling a speed of a motor according to the related art is configured to include; a speed conversion unit 110 that converts a speed indication (command) having a pulse width modulation (PWM) duty type supplied from the outside into an actual speed value (RPM value); a speed detection unit 120 that detects the actual speed of the motor 150; an error calculation unit 130 that calculates a difference (error) between the speed detected by the speed detection unit 120 and the speed converted from the PWM duty value by the speed conversion unit 110, and a speed control unit 140 that applies a new speed indication value to the motor 150 based on the speed error obtained by the error calculation unit 130.
In the apparatus for controlling a speed of a motor according to the related art having the configuration as described above, the calculation for speed detection is performed by periodically obtaining a sample for speed detection at the time of detecting the speed of the motor 150 by the speed detection unit 120. Therefore, the time delay for speed detection calculation occurs and thus, the error in the detection speed value occurs.